Directional antenna with suppressed lobes or ears



E. GERHARD 2,354,254

DIRECTIONAL ANTENNA WITH SUPPRESSED LOBES 0R EARS I y'zs, 1944.

Filed April 17, 1941 2 Sheets-Sheet .1

Fig. 3

INVENTOR ERA/S7 GER/{4RD w gmw ATTORNEY Patented July 25, 1944 jErnst'Gerliard Berlin, (lermanyr vested in the l AlienjPropertyCustodian Application April 117, 1941',

Serial hi /assess I In Germany October 7,- 1939 9Clai1ns. g 1.25 11 andthe second maxima are largely suppressed.

it is known in the prior art. to suppressundee sirable secondary or lateral radiations knownias lobes or ears (that is, secondary maxima) which arise in connection with the operationof a direce tional antenna, for -example, .a sheet antenna," a'paraibola reflector, etc., by making the'current distribution over the entire antenna area vary in such a way that, from a maximum at the cenaerials below one another and staggered with re-,

spect to one another, in the horizontal sense: Thus anyv desired distribution of current, o fa-the' antenna surface or area-is obtainable. A-staggered relationship in the horizontal direction is illustrated by the schematic embodiment, Figure 1.

The antenna shown in Figure 1 may utilize cylindrical parabola reflectors of the kind shown in Figure 2, or sheet radiators comprising a plurality of dipoles, for instance, of the kind shown in Figure 3. A number of the radiators, mounted in one plane staggered with relation to one another, may be assembled to form rhombic antenna such as shown in. Figure 4. Figures 5 to '7 illustrate theoretically determined horizontal diagrams corresponding to the sheet antennae shown alongside the patterns. Figure 2 shows a perspective view of a cylindric parabola reflector 2| which may be used as each of the radiators ll-l4 shown in Figure 1.v The energizing antenna within the reflector is not shown but may be of any conventional type.

Figure 3 shows a broadside array 3| composed of a plurality of individual dipoles 32 so energized by transmission line 33 as to simulate a uniform current sheet. The individual radiating units 3| shown in Figure 3 may be combined as shown in Figure 4 in the practice of the present invention. The combination simulates a rhombic radiating sheet 4|. Due to the longitudinal stagger of the units 3! the desired radiation pattern is obtained.

Figure 5 shows the horizontal diagram of a plain sheet antenna 5| with uniform current distribution of 4). width, x being the operating wavelength.

Figure 6 shows the diagram corresponding to an antenna comprising two surfaces 5| and 6|, each of 4% width, and staggered with reference to each other a distance equal to 4/3l according to the invention. It will be noticed that the first Figure 7, finally, shows theydiagram ofanantenna comprising foursheets; each of-lx width, staggered withrespect'to one another.: The arrange- -ment results from; staggering two-schemes'yas shown in- Figure-G an amount -equalto; \/2 with respect to each other; i In this case the thirdsma'x ximum has been suppressed appreciably asawell as the first and second maxima.

In-the exemplified embodiment of-Figure -l sheet antennae ll,- l2, 13,14, all ofwhichare'ato.

have a uniform'current coveringior distribution; are placedxunderneath one another.; :-'I 'he.fl,ux 1of energy through the vertical sheet.element itindicatedby the dash-lines), is proportional to the antenna surface contained in these surface elements The energy-flux is numerically indicated,-

in relative terms, for each. surface; element. By means of; a variation of the horizontal shift and of the horizontal size of the various antenna surfaces indicated in Figure 1, any desired energy distribution in horizontal sense is attainable, with the result that only the first maximum, or only maxima of a higher ordinal number or all of them may be suppressed. The energy distribution required for each case is ascertainable by calculation by the application of known methods.

It will be understood that what has been shown in the exemplified embodiment for the horizontal direction applies naturally to any other direction. Thusa similar arrangement may be used to reduce undesired maxima in the vertical directivity pattern.

I claim:

1. A directional antenna including a plurality of radiating units, each radiating energy in a pattern having a main lobe and a plurality of supplemental lobes, said units being arranged in a vertical plane normal to the desired line of transmission, one of said. units so being shifted laterally in said plane with respect to another that first and second supplemental lobes are suppressed and radiating units adjacent said one and said other unit being shifted laterally in said plane such distance that third supplemental lobes are suppressed.

2. A directional antenna array including a plurality of radiating units, each unit including a cylindric parabolic reflector having energizing means therewithin, the radiating pattern of each of said units including amain lobe and a plurality of supplementary lobes, the mouth openings of said reflectors having a lateral dimension of the order of several wavelengths, said radiating units being so arranged that the mouth openings of said reflectors he one above the other in a vertical plane, said units being displaced laterally in said plane each with respect to an adjacent unit a distance such that said supplementary lobes are suppressed.

3. A directional antenna array including at least a pair of radiating units, each unitincluding a cylindric parabolic reflector having energizing means therewithin, the mouth openings of said reflectors having a lateral dimension of the order '10 of several wavelengths, said units being so ar"' ranged that the mouth openings of saidreflect'ors lie one above the other in a vertical planefori of said units being displaced laterally in said plane a distance equal to four-thirds of the-bp-g I crating wavelength with respect to the other 4. A directive antenna system including a' pair of antenna arrays, as set forth in claim 3, said arrays being arranged vertically one above the I other and one being shifted laterally a distance equal to one-half of the operating wavelength with resect to the other.

5. A directional antenna array including a pair of radiators each characterized infth'at' at a pre determined position "with-respect to said radiw re we i eiiw wea he -c '7. A directional antenna including a plurality of radiating units, each so constructed that at a predetermined position with respect to said radiator there exists a plane having a uniform field distribution over an area extending transversely of the electric component of said field for a distance equivalent to at least a whole number of wavelengths, said radiators being stacked vertically one above the other and said radiators being displaced laterally in a vertical plane with respect to one another a distance such that supplementary lobes of radiation are suppressed.

' 8;.A'Ldirectional antenna including a plurality of radiatingunits, each so constructed that at a predetermined position with respect to said radiator there exists a plane having a uniform field distribution over an area extending transversely of the electric component of said field for a disr tance equivalent to at least a whole number of wave lenths, said radiators being stacked verticallyirone above the other and-said, radiators being'displaced laterally in a vertical plane with respect to one anoth'erxa distance such that sup-o plementary lobesv of radiation are suppressed,

each "of said radiating units comprising a plurality of vertical dipoles'arranged as abroadsidelarray. v

--9.;A directional antenna array, including 'a pair of radiating units each so constructed that at'a' predetermined position with respect to said radiating unit there-exists a plane havinguniform field distribution over an area extending transversely of the electric component of said field for a distance equivalent to at least a whole number of wave lengths, said radiating units being stacked vertically one above the other and-one of said radiating units being displaced laterally "with respect to the other.

ERNST G ERHARD. 

